Surface electric field on a superconducting wire carrying an AC transport current in an external magnetic field

The penetration of magnetic fields in nonideal type II superconducting wires carrying audio-frequency transport current with a transversally applied static magnetic field has been investigated measuring the field along the surface of straight segments of 10-mil-diameter wire. Oscillographic responses obtained for various frequencies, current amplitudes, and distances between potential probes are described. The application of a limited current density model employed by others for different geometries and forms of excitation to the case of a wire carrying a transport current in an external field is discussed. The oscillographic responses are shown to agree with analytical calculations based on the model, provided that some recognition is given to the magnetic field dependence of the current density parameter.